This page will explain how recurring tasks work in Tasks.
Recurring tasks are a little more complicated in a hierarchical system. There are some aspects of the recurring tasks feature that are a little different, but there are good reasons for the chosen behavior.
Let's look at a simple example: On the first of the month, you set up a task ("Eat Vitamins") due today and tell it to recur every day for a month.
In most systems you would just show each recurrence of the task, but in a hierarchical system it's a little more tricky. Having 30 occurrences of the task show up in the tree view and lists really clutter things up. Besides the clutter, they also affect the % Complete of the parent task (if there is one). From a practical perspective, you certainly don't need to see all 30 reminders at once, either.
To work around these issues, recurring tasks only show up after the previous occurrence of the task is due. Let's go back to our example:
On the first of the month, you see only the original occurrence of the task you created. On the second, the next occurrence of the task appears (you need to configure recurring task activation for this to happen). If the task from the first hasn't been marked complete or deleted, you will see two occurrences of the task.
Note: Future recurring tasks are included in iCalendars.